Current methods for the manufacture of alkylphosphonate monoester are accompanied by undesirable processing conditions, environmentally unfriendly components, and uneconomical by-products. For example, the hydrolysis of alkylphosphonate monoesters is most commonly carried out in an aqueous medium followed by neutralization with a mineral acid. This method however, causes gelation and foaming when applied to hydrophobic alkylphosphonate diesters. Other methods use low molecular weight ketones, such as acetone and methyl ethyl ketone, as solvents in the presence of sodium iodide (NaI). The resulting monoacid salts are converted to free acids with the use of ion exchange resins. Another approach is to use water-miscible solvents, like dioxane and THF, which raise health and environmental concerns. Further, many such methods require processing that involves handling of intermediates in a solid phase. Such handling is undesirable and, furthermore, decreases product yield and purity.
Therefore, a need exists in the art for an improved processing method that is economical, environmentally friendly, and provides an improved alkylphosphonate monoester.